Speaker
Description
The Jiangmen Underground Neutrino Observatory (JUNO), the world's largest liquid scintillator (LS) detector, has started physics data taking since Aug. 26th，2025. The primary goal of JUNO is to determine the neutrino mass ordering. A critical challenge in this measurement is the cosmogenic 9Li/8He background induced by the passing muons. Without suppression, their estimated rate (70~80 per day) significantly exceeds the expected IBD signal rate (~ 50 per day). After muon veto, the rate of 9Li/8He can be reduced to 3~4 per day. This poster presents the muon veto methods in JUNO which mainly relies on the spatiotemporal correlation with muons to reject 9Li/8He, as well as the optimization of the veto cuts to maximize the background suppression efficiency while minimizing the signal loss.